The present disclosure relates to a solenoid valve for controlling fluids, having a shaped spring which is arranged in a working gap between a pole core and an armature.
Solenoid valves are known from the prior art in a variety of embodiments and are used for example in brake systems of vehicles. The known solenoid valves conventionally have a magnet force characteristic in which the magnet force increases very sharply (exponentially) as an axial working gap becomes smaller. Therefore, as the working gap becomes smaller, the solenoid valve can be controlled only with increased actuating forces, and below a predetermined small spacing between the pole pot and the armature, regulation of the solenoid valve is no longer possible. Therefore, in the known solenoid valves, relatively large working gaps are used, such that a valve working range lies in a magnet force range which runs flatter but which at the same time is also of lower magnitude. In particular in the case of solenoid valves which are closed in the electrically de-energized state, however, the available magnet force must be sufficient to open the valve counter to a compression spring which acts in the closing direction. Said compression spring is conventionally designed to be of such a strength that, in the less preloaded state, it can overcome the force of the operating medium acting on the solenoid valve in the opening direction and can close the solenoid valve. Since considerable pressure differences may possibly arise in the operating medium during operation, the compression spring must always provide a force sufficient to ensure that the solenoid valve can be reliably closed even at relatively high operating pressures. This accordingly leads to a compression spring with a relatively high closing force, which in turn has the result that the magnetic circuit of the solenoid valve must provide an opening force which overcomes said spring force. This leads to geometric enlargement of the magnet coil or of other components of the magnetic circuit, which entails not only increased installation space but also additional weight.